For position recognition, in many cases sensors are used that operate according to the Hall sensor principle. For example, for this purpose application-specific integrated circuits (ASICs) can be used as magnetic sensors that, in addition to one or more sensors, for example Hall sensors, can also include an electronics system, for example an electronics system that processes or pre-processes the signals of the sensors. The sensitive elements in the sensors, or the ASICs, are as a rule excited by a movable multipolar permanent magnet, also called an encoder. The signal in the ASICs is generated by the pole transition of the magnetic field (transition from north to south or transition from south to north, referred to hereinafter as a north-south transition without limitation of the direction of transition). The encoder is moved by a coupling with an entraining piece, for example the above-named selector lever. The detection of the position of the encoder by the ASICs is the function of the magnetic sensor element.
For example, in an automatic transmission that is switched manually, the position sensor detects the position of the selector lever and/or selector slide, for example the positions P, R, N, D, S, as well as the intermediate regions, and outputs these to a transmission control device in the form of a code, for example a 4-bit code. For reasons of safety, the coding of the position is as a rule carried out in one step, i.e. two bit changes are always required for the recognition of a new position. The required magnetic field curve (pole transition) is provided to the sensitive elements by the encoder for the correct signal output. However, in the case of a geometrical displacement relative to a specified nominal position, due for example to positional tolerances, distortions of the pole transitions due to the mutual influence of the magnetic poles can cause a deviation of the measured position signal. In order to ensure sufficient sensor precision, the positioning of the slide in all three spatial directions relative to the sensitive elements of the ASICs must have narrow tolerances.
As a rule, the positional tolerances between the sensitive elements and the encoder are a consequence of assembly and/or component tolerances. Thus, a tolerance chain of these tolerances includes for example the positioning of Hall elements inside an ASIC, the positioning of the Hall ASIC in the sensor package, a positioning of the sensor package with respect to a reference point in the overall system, the positioning of the sensor package relative to the encoder, and the positioning of the encoder relative to the entraining element, for example the selector lever (measurement object). However, this tolerance chain represents a considerable challenge for the manufacturing tolerances that are to be realized. This can result in high reject rates and a high economic expense for reject reduction.